Caroline is Gwendolen Chant's alternate in (if we can assume the worlds were gone through in order) [World 12I]?.
(She should not be confused with Caroline Chant, Gwendolen's mother, although for all we know her surname is also Chant.)

She is a queen, in court full of people with elaborate uniforms. People appear to hang on her every word, and appear to follow her every whim. It is all just pretence, however. Caroline is unhappy, and keeps trying to run away.